Java Observer / Observable模式不通知

Question

我正在尝试使用MVC模式使用SWT构建一个简单的Java应用程序。我希望能够在后台发生某些事情时自动更新视图，因此我尝试使用Observer /
Observable模式，但是当Observable更改时，我的Observer似乎从未收到通知。

这是代码：

Launcher.java（主类）

public class Launcher {

    public static void main(String[] args) {
        Application app = new Application();
        PenguinView v = new PenguinView(app);
        Controller api = new Controller(app, v);
    }

}

Application.java（后台应用程序）

public class Application {
    private Penguin _myPenguin;

    public Application() {
        _myPenguin = new Penguin();
        new Thread(_myPenguin).start();
    }

    public Penguin getPenguin() {
        return _myPenguin;
    }
}

Penguin.java（模型，我的可观察对象）

public class Penguin extends Observable implements Runnable {
    private String _color;
    private boolean _isHappy;
    private int _myRocks;

    public Penguin() {
        _color = "Black";
        _isHappy = true;
        _myRocks = 0;
    }

    public void paint(String color) {
        _color = color;
        System.out.println("My new color is " + _color);
        setChanged();
        notifyObservers();
    }

    public String getColor() {
        return _color;
    }

    public void upset() {
        _isHappy = false;
        setChanged();
        notifyObservers();
    }

    public void cheerUp() {
        _isHappy = true;
        setChanged();
        notifyObservers();
    }

    public boolean isHappy() {
        return _isHappy;
    }

    public void run() {
        // Penguin starts walking and find rocks!
        while(true) {
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            iFoundRock();
        }
    }

    private void iFoundRock() {
        _myRocks++;
        System.out.println("I now have " + _myRocks + " rocks");
        setChanged();
        notifyObservers();
    }

}

PenguinView.java（SWT视图，我的观察者）

public class PenguinView implements Observer {
    private Application _app;

    private Display _d;
    private Shell _s;

    private Label _penguinColor;
    private Label _penguinHumor;
    private Label _penguinRocks;
    private Button _upset;
    private Button _cheerUp;
    private Text _newColor;
    private Button _paint;


    public PenguinView(Application app) {
        _app = app;
        _d = new Display();
        _s = new Shell();

        RowLayout rl = new RowLayout();
        rl.marginWidth = 12;
        rl.marginHeight = 12;
        _s.setLayout(rl);

        new Label(_s, SWT.BORDER).setText("Penguin Color: ");
        _penguinColor = new Label(_s, SWT.BORDER);
        _penguinColor.setText(_app.getPenguin().getColor());

        new Label(_s, SWT.BORDER).setText(" Humor: ");
        _penguinHumor = new Label(_s, SWT.BORDER);
        String humor = _app.getPenguin().isHappy() ? "Happy" : "Sad";
        _penguinHumor.setText(humor);

        new Label(_s, SWT.BORDER).setText(" Rocks: ");
        _penguinRocks = new Label(_s, SWT.BORDER);
        _penguinRocks.setText(String.valueOf(_app.getPenguin().howManyRocks()));

        _upset = new Button(_s, SWT.PUSH);
        _upset.setText(":(");
        _upset.addListener(SWT.Selection, new Listener(){
            public void handleEvent(Event e) {
                _penguinHumor.setText("Sad");
            }
        });

        _cheerUp = new Button(_s, SWT.PUSH);
        _cheerUp.setText(":)");
        _cheerUp.addListener(SWT.Selection, new Listener(){
            public void handleEvent(Event e) {
                _penguinHumor.setText("Happy");
            }
        });

        _newColor = new Text(_s, SWT.BORDER);

        _paint = new Button(_s, SWT.PUSH);
        _paint.setText("Paint!");
        _paint.addListener(SWT.Selection, new Listener(){
            public void handleEvent(Event e) {
                //_penguinColor.setText(_newColor.getText());
                _app.getPenguin().paint(_newColor.getText());
            }
        });

        _s.pack();
        _s.open();
        while (!_d.isDisposed()) {
            if (!_d.readAndDispatch()) {
                _d.sleep();
            }
        }
    }

    public void update(Observable obs, Object obj) {
        System.out.println("I go here!");
        _penguinRocks.setText(String.valueOf(((Penguin)obs).howManyRocks()));
        if(obs.equals(_app.getPenguin())) {
            _penguinRocks.setText(String.valueOf(((Penguin)obs).howManyRocks()));
        }
    }

    public void update(Observable obs) {
        System.out.println("I go there!");
    }

Controller.java（控制器）

public class Controller {
    Application _app;
    PenguinView _v;

    public Controller(Application app, PenguinView v) {
        _app = app;
        _v = v;

        // Set observer
        _app.getPenguin().addObserver(_v);
    }

}

输出 ：

I now have 1 rocks
I now have 2 rocks
My new color is Blue
I now have 3 rocks
I now have 4 rocks

您是否知道我在做什么错？

谢谢！

Answer 1

据我所知， PenguinView* 构造函数中的 while 循环阻塞了您的主线程，因此 Controller
永远不会被实例化，而且观察者也永远不会被添加。
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